package com.example.freemarkerDemo.utils.web.handler;

import cn.hutool.core.annotation.AnnotationUtil;
import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.util.ObjectUtil;
import com.example.freemarkerDemo.utils.SpringUtils;
import com.example.freemarkerDemo.utils.StringUtils;
import com.example.freemarkerDemo.utils.mybatis.annotation.DataColumn;
import com.example.freemarkerDemo.utils.mybatis.annotation.DataPermission;

import lombok.extern.slf4j.Slf4j;
import net.sf.jsqlparser.JSQLParserException;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.expression.Parenthesis;
import net.sf.jsqlparser.expression.operators.conditional.AndExpression;
import net.sf.jsqlparser.parser.CCJSqlParserUtil;
import org.apache.ibatis.io.Resources;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.expression.BeanFactoryResolver;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.core.type.ClassMetadata;
import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
import org.springframework.expression.BeanResolver;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.ParserContext;
import org.springframework.expression.common.TemplateParserContext;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.util.ClassUtils;

import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;

/**
 * 数据权限过滤
 *
 * @author Lion Li
 * @version 3.5.0
 */
@Slf4j
public class PlusDataPermissionHandler {

  /**
   * 方法或类(名称) 与 注解的映射关系缓存
   */
  private final Map<String, DataPermission> dataPermissionCacheMap = new ConcurrentHashMap<>();

  /**
   * spel 解析器
   */
  private final ExpressionParser parser = new SpelExpressionParser();
  private final ParserContext parserContext = new TemplateParserContext();
  /**
   * bean解析器 用于处理 spel 表达式中对 bean 的调用
   */
  private final BeanResolver beanResolver = new BeanFactoryResolver(SpringUtils.getBeanFactory());

  public PlusDataPermissionHandler(String mapperPackage) {
    scanMapperClasses(mapperPackage);
  }


  /*public Expression getSqlSegment(Expression where, String mappedStatementId, boolean isSelect) {
    DataPermission dataPermission = getDataPermission(mappedStatementId);
    LoginUser currentUser = DataPermissionHelper.getVariable("user");
    if (ObjectUtil.isNull(currentUser)) {
      currentUser = AdminLoginHelper.getLoginUser();
      DataPermissionHelper.setVariable("user", currentUser);
    }
    // 如果是超级管理员或租户管理员，则不过滤数据
    if (AdminLoginHelper.isSuperAdmin() || AdminLoginHelper.isTenantAdmin()) {
      return where;
    }
    String dataFilterSql = buildDataFilter(dataPermission.value(), isSelect);
    if (StringUtils.isBlank(dataFilterSql)) {
      return where;
    }
    try {
      Expression expression = CCJSqlParserUtil.parseExpression(dataFilterSql);
      // 数据权限使用单独的括号 防止与其他条件冲突
      Parenthesis parenthesis = new Parenthesis(expression);
      if (ObjectUtil.isNotNull(where)) {
        return new AndExpression(where, parenthesis);
      } else {
        return parenthesis;
      }
    } catch (JSQLParserException e) {
      throw new ServiceException("数据权限解析异常 => " + e.getMessage());
    }
  }*/

  /**
   * 构造数据过滤sql
   */
  /*private String buildDataFilter(DataColumn[] dataColumns, boolean isSelect) {
    // 更新或删除需满足所有条件
    String joinStr = isSelect ? " OR " : " AND ";
    //LoginUser user = DataPermissionHelper.getVariable("user");
    StandardEvaluationContext context = new StandardEvaluationContext();
    context.setBeanResolver(beanResolver);
    DataPermissionHelper.getContext().forEach(context::setVariable);
    Set<String> conditions = new HashSet<>();
    for (RoleDTO role : user.getRoles()) {
      user.setRoleId(role.getRoleId());
      // 获取角色权限泛型
      DataScopeType type = DataScopeType.findCode(role.getDataScope());
      if (ObjectUtil.isNull(type)) {
        throw new ServiceException("角色数据范围异常 => " + role.getDataScope());
      }
      // 全部数据权限直接返回
      if (type == DataScopeType.ALL) {
        return "";
      }
      boolean isSuccess = false;
      for (DataColumn dataColumn : dataColumns) {
        if (dataColumn.key().length != dataColumn.value().length) {
          throw new ServiceException("角色数据范围异常 => key与value长度不匹配");
        }
        // 不包含 key 变量 则不处理
        if (!StringUtils.containsAny(type.getSqlTemplate(),
          Arrays.stream(dataColumn.key()).map(key -> "#" + key).toArray(String[]::new)
        )) {
          continue;
        }
        // 设置注解变量 key 为表达式变量 value 为变量值
        for (int i = 0; i < dataColumn.key().length; i++) {
          context.setVariable(dataColumn.key()[i], dataColumn.value()[i]);
        }

        // 解析sql模板并填充
        String sql = parser.parseExpression(type.getSqlTemplate(), parserContext).getValue(context, String.class);
        conditions.add(joinStr + sql);
        isSuccess = true;
      }
      // 未处理成功则填充兜底方案
      if (!isSuccess && StringUtils.isNotBlank(type.getElseSql())) {
        conditions.add(joinStr + type.getElseSql());
      }
    }

    if (CollUtil.isNotEmpty(conditions)) {
      String sql = StreamUtils.join(conditions, Function.identity(), "");
      return sql.substring(joinStr.length());
    }
    return "";
  }*/

  /**
   * 通过 mapperPackage 设置的扫描包 扫描缓存有注解的方法与类
   */
  private void scanMapperClasses(String mapperPackage) {
    PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
    CachingMetadataReaderFactory factory = new CachingMetadataReaderFactory();
    String[] packagePatternArray = StringUtils.splitPreserveAllTokens(mapperPackage, ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
    String classpath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX;
    try {
      for (String packagePattern : packagePatternArray) {
        String path = ClassUtils.convertClassNameToResourcePath(packagePattern);
        Resource[] resources = resolver.getResources(classpath + path + "/*.class");
        for (Resource resource : resources) {
          ClassMetadata classMetadata = factory.getMetadataReader(resource).getClassMetadata();
          Class<?> clazz = Resources.classForName(classMetadata.getClassName());
          findAnnotation(clazz);
        }
      }
    } catch (Exception e) {
      //log.error("初始化数据安全缓存时出错:{}", e.getMessage());
    }
  }

  private void findAnnotation(Class<?> clazz) {
    DataPermission dataPermission;
    // 获取方法注解
    for (Method method : clazz.getMethods()) {
      if (method.isDefault() || method.isVarArgs()) {
        continue;
      }
      String mappedStatementId = clazz.getName() + "." + method.getName();
      if (AnnotationUtil.hasAnnotation(method, DataPermission.class)) {
        dataPermission = AnnotationUtil.getAnnotation(method, DataPermission.class);
        dataPermissionCacheMap.put(mappedStatementId, dataPermission);
      }
    }
    // 获取类注解
    if (AnnotationUtil.hasAnnotation(clazz, DataPermission.class)) {
      dataPermission = AnnotationUtil.getAnnotation(clazz, DataPermission.class);
      dataPermissionCacheMap.put(clazz.getName(), dataPermission);
    }
  }

  public DataPermission getDataPermission(String mapperId) {
    if (dataPermissionCacheMap.containsKey(mapperId)) {
      return dataPermissionCacheMap.get(mapperId);
    }
    String clazzName = mapperId.substring(0, mapperId.lastIndexOf("."));
    if (dataPermissionCacheMap.containsKey(clazzName)) {
      return dataPermissionCacheMap.get(clazzName);
    }
    return null;
  }

  /**
   * 是否无效
   */
  public boolean invalid(String mapperId) {
    return getDataPermission(mapperId) == null;
  }
}
